Pharmaceutical Powders for External Use

Powders for External Use

• Powders for external use are commonly used on skin, they can contain medicaments or be simple dusting powders.
• Finely divided powders are typically produced using a sieve with a size of 180 µm.
• Mixing ingredients for external powders is done using the "doubling up" method.
• External powders should be sterilized if they are to be used on large areas of open skin or wounds.
• Talc, kaolin, and other natural minerals used in powders can be contaminated with bacteria like Clostridium tetani and C. Perfringens.
• To prevent contamination, ingredients should be sterilized using dry heat or the final product should be sterilized.
• External use powders should not be used on areas with significant exudates as it can lead to hard crust formation.
• Powders for external use should be stored in cool, dry places and labeled as "for external use only."
• Examples of official external use powders include zinc oxide dusting powder compound BP, chlorhexidine dusting powder BP, and talc dusting powders BP.
• Proprietary examples of external use powders include antifungal and antibacterial powders.

Insufflations

• Insufflations are medicated powders blown into body cavities like ears, nose, and throat using an insufflator.
• Traditional insufflations have declined in use due to their inconvenience and inelegance compared to other topical preparations.
• Ensuring accurate dosing with traditional insufflators for systemically active drugs was difficult.
• Modern insufflations can deliver potent drugs like sodium cromoglycate directly to the lungs for rapid absorption.

Tablets

• In 1843, William Brockedon patented a machine for compressing powders into tablets.
• A tablet is a solid preparation containing a single dose of one or more active ingredients, formed by compressing uniform particles.
• Tablets are mainly used for systemic drug delivery but can also have local effects.
• For systemic use, the drug must be released from the tablet, depending on the formulation, this can occur via chewing, dissolving, or other mechanisms.
• Tablets are classified by their intended route of administration: swallowing whole, chewing, dissolving in water, or retention in the mouth.
• Tablets require a variety of excipients, depending on the type of tablet and the desired properties.
• For systemic use, tablet formulations aim to achieve a controlled release of the active drug over a defined period.
• Tablets are typically packaged in blister packs, bottles, or tubes for protection and to ensure dosage accuracy.

This quiz covers the essential aspects of powders used for external application, including their composition, preparation methods, and safety precautions. It also discusses common ingredients and the importance of sterilization to prevent contamination. Test your knowledge on this critical area of pharmaceutical practices.